Sinuses are cavities inside the structure of our skull. When we lose a tooth, the bone around the root area starts to recede. This can lead to the sinus expanding into the tooth root area. If you choose to have an Implant, there may not be sufficient bone to support it. Special material can be inserted to encourage bone re-growth and ‘lift’ the sinus. Over time, the bone will re-grow, providing enough bone to support the Implant.